Coronatae

(invertebrate zoology) An order of the class Scyphozoa which includes mainly abyssal species having the exumbrella divided into two parts by a coronal furrow.

An order of the class Scyphozoa which includes mainly abyssal species. The exumbrella is divided by a circular or coronal furrow into two parts, an upper central disk and a lower coronal part. The central disk is usually domelike, but in Periphylla (see illustration) it often narrows toward the top. The coronal part has gelatinous thickenings (pedalia) situated on the radii running from the center of the umbrella to the tentacles and the sensory organs. The pedalia are separated from one another by clefts, running down the radii, that are half-way between each tentacle and rhopalium (a sensory organ). Abyssal forms of this group are dark brown or reddish-purple. The littoral species of Nausithoë is reported to show alternation of generations, but the life history of abyssal forms remains unknown. See also Scyphozoa.

Periphylla. (After L. H. Hyman, The Invertebrates, vol. 1, McGraw-Hill, 1940)